A vehicle seat of the prior art includes a backrest frame, a collision detector provided in the backrest frame for moving backward when an occupant moves backward relatively to the backrest frame due to rear-end collision, and a headrest attached to the backrest frame, movable between an ordinary support position and a head protecting position ahead of the ordinary support position, and moving from the ordinary support position to the head protecting position when the collision detector moves backward.
Patent document 1: Japanese Patent Application Laid-Open No. 10-119619